1. Technical Field
The disclosed subject matter relates generally to the field of nerve stimulation. More specifically, the invention relates to a method and system of optimizing parameter settings for nerve stimulation.
2. Background Information
Various diseases and disorders of the nervous system are associated with abnormal neural discharge patterns. One treatment regimen for such diseases and disorders includes drug therapy. Another treatment technique includes the implantation of an implantable medical device having a pulse generator for electrically stimulating (i.e., applying an electrical signal to) a target location of the patient's neural tissue, such as a cranial nerve. In one such available treatment for epilepsy, the vagus nerve (the tenth cranial nerve) is electrically stimulated by a neurostimulator device substantially as described in one or more of U.S. Pat. Nos. 4,702,254, 4,867,164, and 5,025,807, all of which are incorporated herein by reference.
Some implantable pulse generators used for electrical stimulation of neurological tissue operate according to a therapy algorithm programmed into the device by a physician or other health care provider. One or more therapy parameters or the actual software running on the neurostimulator may be changed after implantation by reprogramming the neurostimulator via transcutaneous communication between an external programming device and the implanted neurostimulator. The ability to program (and later re-program) the implanted medical device (“IMD”) permits a health care provider to customize the therapy provided by the IMD to the patient's needs, to update the therapy periodically should those needs change, and to update the software of the device, including the operating system, as improved and/or revised therapy regimens are developed.
However, in many cases, the physician will not know a suitable or optimal range of parameter settings within which to operate the neurostimulator. Each patient may have different levels of tolerance and reaction to nerve stimulation. Thus, some patients may have to be stimulated differently (e.g., different current levels, different frequencies, etc.) than other patients to respond to the therapy. Complicating selection of nerve stimulation therapies and parameters is the fact that many implantable medical devices are battery-operated. Different therapies may result in a different level of drain on the device's battery. All else being equal, one would prefer for the battery to last as long as possible.